基于有限元法的回转式空气预热器波纹式弹性密封结构的优化设计

基于有限元法的优化设计方法,采用有限元通用软件ANSYS的优化设计模块对波纹式弹性密封进行三维参数化建模,并编制APDL命令流,建立优化设计分析文件对波纹式弹性密封结构进行了优化设计分析.结果显示.得到一组波纹式弹性密封的最优结构,波纹式弹性密封的弹性增加约68%.有限元法结合优化设计对选择波纹式弹性密封结构方案具有显著效益.     

以刚度控制的重型钢结构厂房排架柱截面的优化设计

对传统的结构设计和结构的优化设计做了简要的分析对比,应用结构优化设计理论—数学非线性规化中的复形法对重型钢结构厂房排架进行了优化设计,编制了电算程序,得到较好的收敛结果．     

浅谈结构动态优化设计在冶金设备中的应用

介绍了结构动态优化设计技术的发展现状,及采用有限元分析软件进行结构建模和结构动态优化设计的一般步骤,阐述了在冶金设备设计中应用该技术的重要性及前景.     

基于渐进变分法的蛋盒型结构等效刚度分析及优化

对蛋盒型结构的等效刚度特性进行了分析并实现了蛋盒型结构参数的优化设计.首先以蛋盒型结构的单胞为研究对象,基于渐进变分法,得到了蛋盒型结构等效刚度特性的数值计算方法.随后用该方法计算蛋盒型结构不同参数情况下的等效刚度特性,并以结构参数为自变量,等效刚度特性为因变量进行拟合.最后应用拟合公式在限定泊松比或等效刚度的情况下,分别以最大化结构的屈曲载荷和最大化单位质量吸能能力的优化为例,对蛋盒型结构参数进行了量纲为一的优化设计.计算结果表明:蛋盒型结构拉伸刚度降低,弯曲刚度升高;蛋盒型结构的刚度特性与结构参数之间呈现非线性的特点,结构表现出负泊松比的特性;在给定优化目标和限定条件时应用拟合公式可以快速实现蛋盒型结构参数的主动优化设计.      

应用优化设计法改造水压机横梁

研究了常用优化设计方法在新的水压机活动横梁中的应用,对活动横梁的结构参数进行了优化,保证设计方案达到最佳;并建立了活动横梁的有限元力学模型,对该结构进行了三维有限元强度分析.     

链篦机传动系统多目标优化设计

由于链篦机工作在高温、热应力交变等恶劣环境下,其传动系统设计需要综合考虑传输效率、传动能力、精度与热膨胀预留间隙等多方面因素。采用线性加权法的多目标优化设计理论,以传动件的结构尺寸和使用要求为优化约束条件,以篦床重量和链传动的最大传动能力为优化目标,对链篦机传动系统整体结构和传动方式进行优化设计。建立了链篦机传动系统各子目标和总目标优化数学模型,并利用MATLAB仿真软件进行优化设计验算。优化设计结果用于设备生产,取得了良好效果。     

堆垛机组导向装置的优化设计

堆垛机组导向装置的优化设计经导柱式导向装置、早期连杆式导向装置、新型连杆式导向装置三个过程，通过不断的技术改进，产品得到逐步完善。本文从优化设计角度，分析原有结构的不足，推出导向装置的新型结构形式并提高了堆垛机组导向装置的动力臂幅度，使机组动作更加灵活、可靠。     

6m焦炉推焦车平煤杆技术改造

文章介绍了6 m推焦车平煤杆的结构及功能,并介绍了其在在生产实践中出现的故障形式,详细地分析了原因。为此,对其进行了优化设计,并针对性提出系列改进办法,改进后提高了强度、结构刚性、使用寿命,达到平通、压紧、压实的作用。     

基于当量小球模型蓄热烧嘴内腔尺寸的新算法

在济钢中板厂3#加热炉设计中,提出了基于当量小球模型蓄热烧嘴内腔尺寸的新算法,并据此对烧嘴进行了结构优化设计,经使用获得了良好的效果.     

轧机辊身结构优化设计与加工

论述了在辊身结构设计和工艺方面所做的改进,对辊身结构进行了分析和优化设计,并分析了工艺设计路线,给出了具体工艺步骤,产品达到客户要求.     

Sources of Changes in Design–Build Contracts for a Governmental Owner

In recent years, many U.S. federal, state, and local governments have been authorized to use the design–build method of project delivery instead of the traditional design–bid–build method. Recent studies have not been definitive on the cost advantage of design–build for governmental owners. There are fewer change orders in design–build due to design errors because the designer (architect/engineer) and contractor are one entity, but there are other causes of change orders. Some literature suggests that changes requested by the owner of the facility are greater with the design–build method. This research examines the causes for construction-phase changes in 14 design–build and 20 design–bid–build projects. Total changes, expressed as number per contract, cost per contract, or percentage of original contract, were significantly lower in design–build. Fewer design errors in design–build accounted for this advantage. The number of owner-requested changes was significantly greater in design–build. The cost of owner-requested changes, averaged over all the projects, was significantly less for design–bid–build. The differences in changes due to differing site conditions were not significant. The concept that there are more owner-requested changes in design–build projects is supported by this research.     

微电机后盖栅格多工位级进模设计

详细介绍了微电机后盖栅格的设计方案、设计步骤及结构设计。该设计适用于大批量生产，材料利用率高，便于实现自动化。     

Parallel Computing Techniques for Sensitivity Analysis in Optimum Structural Design

Among different activities of the optimum structural design using the gradient-based optimization approaches, design sensitivity analysis is the most time-consuming computational process. By introducing parallel computing techniques for sensitivity computation, significant speedup has been obtained in optimum structural design. Computation of design sensitivities is characteristically uncoupled, thus opening the door to parallelization. In this paper, two types of approaches viz. single-level and multilevel parallelisms are pursued for design sensitivities. The design sensitivities are computed using analytical and finite-difference methods. Numerical studies show that the performance of the parallel algorithms for design sensitivities on message passing systems is very good. Good speedups have been achieved in parallel multilevel sensitivity calculation. The parallel algorithms for design sensitivity analysis have been implemented on message passing parallel systems within the software platform of Parallel Computer Adaptive Language.     

Hydraulic Considerations in Geosynthetic and Aggregate Subsurface Drains

The hydraulic design of certain types of subsurface drains has recently been put on a more rational footing, and deficiencies in earlier design methods have been demonstrated. However, significant limitations remain in hydraulic design methods for geosynthetic and aggregate subsurface drains. It is important to decouple the groundwater hydrology from the internal hydraulics of the drain, and properly design subsurface drains for open-channel rather than pressurized conditions. Present design methods can inadvertently result in pressurized flow. The assumption of uniform flow (Manning’s equation alone) is also improperly made in some present design methods. Consequences can include unintended pressurized flow and attendant nonuniformity of inflow on the one hand and uneconomical design on the other. Current standard guidelines provide relatively little guidance for the design of geosynthetic and aggregate drains. A current ASTM standard, commonly referenced by geosynthetic manufacturers, has significant limitations. Deficiencies and qualifications are identified for present design methods. Guidance is given for the improved design of geosynthetic and aggregate subsurface drains based on sound hydraulic principles.     

Steel Girder Design per AASHTO LRFD Specifications (Part 2)

This is the second of two companion papers discussing and illustrating the AASHTO LRFD Bridge Design Specifications for the design of steel girders subject to flexure and shear. In the first paper, notation was introduced that allows reformulation of the AASHTO design equations in a more convenient format and the design of steel I-girders in flexure was presented. The second paper addresses design of box girders for flexure and design of box and I-girders for shear. The design approach is illustrated by two detailed example problems.     

Bioinspired Computational Framework for Enhancing Creativity, Optimality, and Robustness in Design

This paper presents results of transdisciplinary research on the development of a bioinspired computational framework for engineering design. This framework is intended to support design by addressing three critical design objectives, including novelty, optimality, and robustness. It provides several computational models and methods, which are inspired by fundamental processes occurring in nature, and discusses their potential for enhancing design. They include models and methods for evolutionary, developmental, and coevolutionary design. Their use is illustrated with examples from the area of steel structural design ranging from a simple cantilever beam design problem to a much more complex problem of designing wind bracings in tall buildings. The paper also shows how several methods and models can be integrated and form a coherent bioinspired computational framework for engineering design.     

Identifying a Design Management Package to Support Concurrent Design in Building Wafer Fabrication Facilities

Concurrent design is commonly used in building a semiconductor wafer fabrication facilities to shorten projects. Current practice in managing a design schedule involves preset milestones that represent percentages of completion. Such a simple control scheme does not provide sufficient information to support concurrent design. This study presents an analytical model that applies a cluster identification algorithm to separate the work of designing a multisystem project into management packages that support concurrent design. Tasks within a package have strong informational dependency relationships on each other, and are not suited for concurrent design. Tasks of different packages have weak dependency relationships on each other, and are suited for concurrent design. Tendering design work based on these packages may reduce the number of design interfaces between participating design firms. Possible application of the model includes the management of design schedule, design contract tendering, and design information flow.     

Concept for Type-Local Instance–Global Instance Object Modeling and Application to Structural Design of Buildings

Rational data modeling is prerequisite to the computerization of design, and the use of design information in the subsequent work, in areas such as cost estimation and construction. In particular, the structural design of buildings consists of a long series of unit steps and is nonprocedural and data intensive compared with structural analysis problems that are procedural and computation intensive. Hence, there is a need to investigate the characteristics of the problem and to structure design information properly to effectively manage it in the structural design process. This paper discusses modeling concepts for managing design information efficiently and supporting the design process effectively. Type-local instance–global instance object modeling is the conceptual backbone of the model in this study and provides consistent modeling of structural components including not only primitive members such as beams and columns, but also composite elements such as floors, frames, and even whole buildings. This paper also provides core and extended object concepts for classifying structural design information into an overall design and for processing dependent temporary stages in the design. Foundational and application object concepts are introduced for extending the model to various types of structures. An integrated structural design system for buildings is developed based on these modeling concepts, and finally a brief discussion of the application of the object model throughout the entire structural design process in the integrated structural design system is given. It is expected that the modeling concepts proposed in this research can be applied to a range of other engineering applications.     

Solidworks软件在工业炉窑设计中的应用

以三维设计软件Solidworks为平台,分析利用Solidworks进行工业炉窑三维设计的优势,介绍应用Solidworks进行工业炉窑三维设计的成果,阐述应用Solidworks对提高设计质量和效率的作用。     

Parametric Coordinator for Engineering Design

Coordination of design information is essential for the design team to provide accurate technical documents for the actual construction. Design changes are inevitable during any ordinary building project. If the design changes are not properly managed, design conflicts will be created, which will result in more expensive design or even failure in the design-construction process. However, little research has been done to address the issue and thereby provide tools for the management of design changes. This paper presents a novel approach that can facilitate the coordination of design information through managing design changes with the help of a parametric coordinator. Design changes of dimensions between different building components are specially discussed. The proposed parametric coordinator provides each building component with the linking knowledge that is described as a dimensional property and a reference property. A group design method is applied to check the design consistency. Illustrative examples are presented to demonstrate the feasibility of the proposed parametric approach for design change management.